The operator of a cabin cruiser that rammed and killed a man on a smaller fishing boat in a San Francisco Bay accident near Brisbane was convicted Thursday of two misdemeanors.

Minh Truong, 30, and his father were on a 17-foot boat when they were hit by a 42-foot pleasure boat operated by Phillip Larson off Sierra Point on Aug. 3, 2011.

Truong drowned after he was caught underneath his capsized boat. His father clung to the hull and was rescued.

A San Mateo County jury convicted Larson, 77, of misdemeanor manslaughter and a violation of the state navigation code. He faces up to a year in jail for each charge.

An analysis by the U.S. Coast Guard concluded that Larson had plenty of time to see Truong's boat and that Larson, as the operator of the larger vessel, had a duty to yield.

Larson's girlfriend and another couple were also on the larger boat, said Matthew Davis, an attorney who filed a lawsuit against Larson on behalf of Truong's fiancee and their two children that is still pending.

Larson told investigators that his boat was on autopilot and he was below deck at the time of the crash, Davis said.

Larson crashed a boat into a fixed pier in 2005, badly injuring at least one passenger, said Davis, adding, "He obviously learned no lessons from that experience."